Quick Guide to the EPA on Drinking Water

quick guide to the epa on drinking water

The following article is intended to help US residents understand the EPA’s position on where our water comes from, the potential contaminants, and the EPA’s three Drinking Water Standards that regulate water testing in our country.


For more information about the following, please see our Guide to Drinking Water:

  • Testing (Public and Private Water)
  • Maintenance Best Practices
  • Preventing Lead and Bacterial Contamination
  • Bottled Water
For more information specifically about Asheville and WNC Drinking Water.

EPA Drinking Water Standards

The EPA sets legal limits on over 90 contaminants in drinking water.  The EPA maintains two standards for drinking water- the Primary Standards include enforceable limits on harmful contaminants, and the Secondary Standards include unenforceable guidelines for ‘nuisance chemicals.’  The EPA also maintains a list of contaminant candidates called the CCL, which it continues to study and consider for future regulation.

  • Primary Standards

    • Enforceable limits on harmful contaminants
  • Secondary Standards

    • Unenforceable guidelines for ‘nuisance chemicals’
  • Contaminant Candidates or CCL

    • Candidates being studied for potential future regulation

    Primary Standards

    These standards apply to contaminants known to cause harm in high quantities.  The Primary Standard is legally enforceable, and that applies to all public drinking water.  The complete Primary Drinking Water Regulations can be found here. The Primary Standards regulate a list of contaminants known to cause health issues, such as

      • Microorganisms

        • (Giardia, E. Coli, etc.)
      • Disinfection Byproducts/Disinfectants

        • (Bromate, chlorine, etc.)
      • Inorganic Chemicals

        • (Arsenic, Mercury, Lead, Nitrite/Nitrate, etc.)
      • Organic Chemicals

        • (Glyphosate, PCBs, VOCs, etc.)
      • Radionuclides

        • (Uranium, Radium, etc.)

      Secondary Standards

      These Standards apply to ‘nuisance chemicals’ and, in general, do not pose a risk to human health.  According to the EPA, these standards are non-enforceable guidelines. They include a list of contaminants that may cause cosmetic defects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water.  Find the complete EPA Secondary Drinking Water Standards.

        • Metals

          • Aluminum, Chloride Copper, Iron, Manganese, Silver, Zinc

        • Physical Qualities

          • Color, Corrosivity, pH, Odor, Total Dissolved Solids

        • Foaming Agents

        • Fluoride

        • Sulfate

        Contaminant Candidate List (CCL)

        This is a list of drinking water contaminants known or anticipated to occur in public water systems and are not currently subject to EPA regulations.  The EPA uses the CCL to identify priority contaminants for regulatory decision-making and information collection.


        Sources of Drinking Water

        According to the EPA, nearly all drinking water in the US comes from fresh surface waters and groundwater aquifers. Various chemicals, microbes, and radionuclides can contaminate these sources. 

        Public Drinking Water

        Public drinking water is subject to EPA Federal regulations and the Safe Drinking Water Act (well systems with more than 15 connections or serve 25 or more individuals are considered public water).  Public Water is monitored and tested regularly, accounting for the legally enforceable Primary Standards.

        Private Drinking Water

        Private wells or spring owners are responsible for protecting their drinking water. No enforceable Federally programs regulate private drinking water (less than 25 individuals or less than 15 connections).  State programs exist for permitting, inspecting, and testing private drinking water; however and local County Environmental Health Departments work with State Laboratories to provide water testing for owners of private wells.  The State Laboratories test water according to EPA Primary and Secondary standards (see below)

        Bottled Drinking Water

        It is the FDA’s responsibility to ensure that quality standards for bottled water are compatible with EPA standards for public drinking water.

        Potential Contaminants

        According to the EPA, there are four primary sources of drinking water contamination:

        • Industrial and Agricultural

          • (pesticides, fertilizers, solvents, heavy metals, petroleum products, etc.)
        • Human and Animal Waste

          • (Giardia, Cryptosporidium, E. Coli, etc.)
        • Treatment and Distribution

          • (Disinfection Byproducts, Disinfectants, etc.)
        • Natural Sources

          • (Arsenic, Heavy Metals, Radionuclides, etc.)

        Well Inspections and Water Testing in Asheville and WNC

        Our Company, Builder Buddy Inspections & Testing, provides Well Inspections, Septic Inspections, Water Testing, and other Inspection services.  We are a highly-rated Well Inspection company based out of Asheville that provides high-quality inspection and testing reports and services.  If you are located within 40 miles of Asheville call us today to set up an appointment or schedule here.

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